A new study published in Current Biology challenges the long-held belief that spiders originated on land. Researchers examined the fossilized brain of a Cambrian-era creature, *Mollisonia symmetrica*, finding its central nervous system strikingly similar to that of modern spiders. This suggests arachnids may have evolved in the ocean, contradicting previous assumptions based on fossilized external features. The study's authors highlight the unique backward brain structure common to both *Mollisonia* and modern arachnids, supporting their hypothesis. Further research is needed to fully understand the evolutionary implications.

Prepared by Olivia Bennett and reviewed by editorial team.